The present invention relates to a method of manufacturing a connecting element, particularly for window and door frames, facade walls and the like.
Connecting elements for window and door frames, facade walls and the like are known in the art. A known connecting element has two metallic profiled members which are spaced from one another and provided with projections, undercuts and the like at their surfaces facing toward one another. Two insulating inserts extend in the direction of elongation of the metallic profiled members, are constituted of heat-insulating material and separated from one another by an intermediate hollow space. Each insulating insert is separated from the intermediate space by a separating member which extends between the metallic profiled members and forms a bottom of a respective one of sections formed in a hollow space between the metallic profiled members. In order to form the insulating inserts, a thermoplastic synthetic material is poured in castable state into the above-mentioned sections of the hollow spaces between the metallic profiled elements. First of all, the first section of the inner hollow of the connecting element is placed under a casting arrangement and filled with insulating material. When the material is hardened in the first section of the hollow space of the connecting element, it is turned about its longitudinal axis, and then the second section of the hollow space is filled with this material.
One of the known methods is disclosed in the German Auslegungsschrift No. 2 531 221. In accordance with the disclosed method in this patent, two individually extruded metallic profile members serve as an initial element. In order to retain the metallic profiled elements at a distance from one another, separating members of heat insulating material are inserted between the profiled members so that the separating members extend in the direction of elongation of the latter, and the metallic profiled members are prefixed thereby. Each separating member forms a respective bottom of a section which is formed between this bottom and the inner walls of the metallic profiled members. The separating members remain after pouring of the material into the sections of the hollow space and hardening the same, as relinquished parts in the finished connecting element.
Such a method has the essential disadvantage in that for manufacturing the connecting element special auxiliary molds are necessary, in order to fix the metallic profiled members at a distance from one another in their final positions. The reason for this is that the prefixing attained by the separating members does not provide in practice for high accuracy of size of the connecting element, because substantial play is necessary for inserting the separating members between the metallic profiled members. In accordance with the known method, the insulating inserts are formed by an insulating foam material which expands in its volume until it hardens. Thereby, precautionary measures must be taken in order to prevent flowing of the insulating material out of the sections of the hollow space during the foaming process.
Another method is disclosed in the German Pat. No. 1 174 483. In accordance with this method, a one piece initial profiled element is utilized, and metallic connection of this profiled element terminates after filling a hollow space with insulating material and hardening of the same, by removing metallic bridges. This profiled element does not require auxiliary forms for its manufacture. However, in accordance with this method it is impossible to manufacture connecting profiled elements in which two or more insulating inserts are provided at a distance from one another. Such a connecting profiled element has the advantage in that it makes possible on economical grounds a wide selection of insulating materials for the insulating inserts, which are available at the market and differ in their heat conductivity, physical properties, casting characteristics, hardening time and so on.